This invention relates to a supplemental occupant restraint system for an automobile of the air bag type. More particularly, the invention is directed to an air bag module including a retainer for holding the air bag cushion in position relative to the module, wherein the retainer is secured to the module by engaging an inflator.
Air bags are well known supplemental restraint systems in widespread use for the safety of automobile occupants. Air bags systems have been developed that typically comprise three basic subsystem groups. These groups include impact sensors and associated wiring, diagnostic devices and air bag modules. The third group, the air bag module, is the subject of the present invention.
The air bag module has been developed for assembly in a modular form and is primarily a complete packaged unit for installation in the automobile interior and connection to the other subsystems during assembly of the vehicle. The air bag module typically comprises a container that serves as both a housing and a reaction device, an inflator that includes a gas generation mechanism, and a cushion that is folded, inserted into the container and attached to the container. When necessary, a means for directing a deploying cushion from the container into the passenger compartment of the automobile is included, generally in the form of a chute that may be integral with the housing. The air bag module is typically covered with a deployment door or doors on the automotive interior side of the module to provide a complete enclosure for the folded cushion and through which the cushion is deployed. The container is normally made of sheet metal with the cushion carried near the opening and the inflator mounted near the back of the container thereby forcing the cushion to deploy through the door when the inflator releases gas during discharge. The air bag module is typically connected to the automobile structure via the reaction container.
An alternate type of air bag module eliminates the container by utilizing the supporting structure of the automobile's instrument panel to house the cushion and inflator. With this type of module the assembly includes an inflator, a skeletal inflator support and the cushion which is positioned atop the inflator and is held in place by a cover. This type of module is attached to the integral instrument panel housing.
The housing is the element of the air bag module to which all of the other module components generally attach. In either of the above described modules the cushion must be connected to the housing in a manner allowing it to receive the discharged gas from the inflator, and when deployed to be spatially positioned in an appropriate location within the automobile's passenger compartment. Several fastening means have been used to hold the cushion in location. A partial list includes: bolts, rivets, rings, clips, rods and hooks. These fasteners are used to attach the perimeter of an opening in the cushion to the perimeter of an opening in the housing. This attachment method allows the gas generated by the inflator to pass through the opening in the cushion. Inflator discharge causes the cushion to unfold and inflate while forcing its way through the cover and to present itself in an inflated state within the passenger compartment of a vehicle.
The cushion is generally fabricated from a material that is suitable for sewn construction and typically includes a sewn hem forming the opening through which gas discharged from the inflator is directed. This opening forms a gas inlet or throat of the inflatable cushion. The hem may be sewn to engage a ring or a rod for fastening to the housing or the cushion may be connected directly to the housing with fasteners such as bolts, rivets or similar devices.
The inflator generates the gas used to deploy and inflate the cushion. The inflator is a weighty device. The effort needed to manipulate the module is increased after it is included in the assembly. Therefore, it is preferable to assemble the remaining components of the air bag module and add the inflator in a final operation of the assembly or possibly at a later time prior to installation in the automobile. In either case the remaining module components must be designed to attach together prior to the addition of the inflator.
It is desirable to reduce the number of fasteners used between the cushion and the housing. It is also desirable to more directly fasten the cushion to the inflator. Such a simplified construction can facilitate assembly of the module. However, as noted above the inflator may be the last component added to the module thereby limiting flexibility in the assembly process, thus complicating a solution to the present problem.